1. Field of the Invention
This invention is directed to microelectronic grade substrates and related metal-embedded devices and methods for making such substrates and related meal-embedded devices.
2. Related Art
Embedding sensors into a mass of material allows the sensors to sense the value of a parameter of the mass in a way that often is not possible with surface mounted sensors. Some material data, such as that relating to the internal thermal and mechanical properties of the material, can only be collected in situ by sensors. For example, internal temperature and strain data is obtained by embedding sensors into a component, with information from remote areas being extrapolated from an array of such sensors. Moreover, due to the shape, size and/or use of the sensor and/or the device being sensed, mounting the sensors to the outside of the mass of the material might not always be possible. Such material masses include tools, dies, and the like, such as molds, drill bits, and cutter bits, elements of machines, such as turbine blades of aero-engines, static components of machines and systems, such as pressure vessels and pipes, and the like.
Published Patent Application 2004/0184700 to Li et al. discloses a number of embedded sensor structures. In FIGS. 3-4B, the '700 published patent application discloses a number of embodiments of an embedded sensor. In FIGS. 4A and 4B, the '700 published patent application discloses a method for forming a thin film microelectronic sensor on a metal substrate, then putting an encapsulating metal layer over the thin film sensor.
The '700 published patent application discloses a method for embedding a thin-film sensor in a high temperature metal bulk material. This method calls for a thin-film sensor to be fabricated on the surface of a metal substrate. First, an insulating or dielectric layer is deposited on the surface of the metal substrate. Then, a thin film sensor is fabricated on this surface using standard photolithographic processes. The sensor is then coated with an insulating ceramic layer, coated with a thin seed layer of the metal matrix material, and electroplated with the same bulk metal matrix material to further encapsulate the sensor. The sensor can then be surrounded by the bulk material by casting or by using a similar process, placing the sensor at the appropriate location within the fabricated component. The '700 published patent application also describes a number of methods for embedding fiber optic sensors in a high melting temperature bulk material and for collecting data from an embedded sensor.